Rock Around The Clock

My friend Chandoo proposed a chart to show website traffic vs. time of day in Plot your data around the clock [Excel charting idea]. He thought he’d use the analogy of a 12-hour analog chart, and put a bubble at each hour, where the size of the bubble is related to the pageviews during that hour. Well there’s 24 hours in a day and 12 hours in a clockface, so he had to make a pair of charts. Here’s the result:

Chandoo's Double Bubble Chart Around the Clock

Well, this probably seemed like a good idea at the time, and I like the fact that Chandoo keeps trying new ideas and shares them with his readers. But this dual chart has some shortcomings. The chart reminds me of a pair of Elton John glasses with jewels all around the frame, or maybe if I draw a few lines, it looks like a bicycle. And Dubble Bubble is a brand of chewing gum, not an Excel chart type. [Read more…]


Peltier Tech Charts for Excel

Suicide Rates in Japan

In Can You Improve this Graph Showing Suicide Rates in Japan?, Nathan of FlowingData shows a chart of long-term unemployment rates and suicide rates in Japan. The chart comes from Suicide Epidemic in Japan.

What’s wrong with this chart (which I’ve reproduced below)?

  • Axis label is faulty. “Japan and Suicide Rate” should be “Japan Long Term Unemployment and Suicide Rates”.
  • Rates are not defined. Suicide Rate is number of suicides per 100,000 population. Long Term Unemployment Rate is percentage of total unemployed who have been unemployed for over twelve months.
  • Frequency of data is different. Using markers as in my version, it is clear that suicide rates are reported with much less frequency than long term unemployment. At least they didn’t use smoothed lines*.
  • Such unrelated rates should not be plotted on the same axis. This chart makes it look like the rates were about the same in 1980, then unemployment dropped below suicides, then it rose above suicides, then both remained the same from about 1992 through 2000. [Read more…]


Peltier Tech Charts for Excel

Adding an Arbitrary Target

In yesterday’s post, Add a Target Line, I showed how to add a simple horizontal line target indicator to a chart. What if your target isn’t constant. I’m not talking about your boss’ moving target, but a case illustrated by the following dummy data. Our company makes widgets, which are more popular in spring and summer, as well as at the year end holidays. Most of the year our target is 20 units, but from April through August the target is 25, and in December we aim for 30 units.

We could simply create a line chart to show both the target and actual values. However, the target looks too much like the actuals, and we’d like them to look more different, so they can be distinguished at a glance.

[Read more…]


Peltier Tech Charts for Excel

Add a Target Line

Usually in order to characterize plotted data more completely, it helps to add a target line to your chart. There are a number of ways to do this in an Excel chart. If your chart is a column chart, you can add another column series, you can add a line series that spans the middle of the first column to the middle of the last, you can add an XY series that spans the entire chart, or you can add an XY point with an error bar that spans the chart.

We are plotting how five employees of our widget factory perform against their target of 22 widgets. Here is the data; ignore the extra data beyond column C for now.

A plain chart of the employees’ performance is shown here. This column chart was created using the data in A1:B6. [Read more…]


Peltier Tech Charts for Excel

Peltier Tech Charts for Excel 3.0